Bioactive compounds extracted from marine organisms showed several biological activities. The present study is an extension of our earlier studies where we assessed the antiproliferative and pro-apoptotic activities of ethanol, methylene chloride, ethyl acetate, acetone, and chloroform crude extracts of sponges: Negombata magnifica (NmE) and Callyspongia siphonella (CsE) against cancer cells. Herein, we are extending our previous findings on both sponge species depending on an alternative methanol extraction method with more advanced molecular biochemical insights as additional proof for anticancer and antimicrobial activity of N. magnifica and C. siphonella. Therefore, sponge specimens were collected during winter 2020 from the Dahab region at the Gulf of Aqaba. Each sponge was macerated with methanol to obtain the crude extracts; NmE and CsE. GC–MS analysis presented a total of 117 chemical compounds; 37 bioactive, 11 represented previously as constituents for a natural organism, and 69 had no biological activities. NmE dose-dependently inhibited the growth of HepG2, MCF-7, and Caco-2 carcinoma cell lines compared to CsE, which unfortunately has no antiproliferative activity against the same cancer cells. NmE was found to induce G0/G1 cell cycle arrest in HepG2 cells with its inhibition for CDK6, Cyclins D1, and E1 in HepG2, MCF-7, and Caco-2 cells. NmE also activated ROS production in HepG2 cells and induced apoptosis in HepG2, MCF-7, and Caco-2 cells via an increase in pro-apoptotic protein Bax, caspase-3, and cleavage PARP, and a decrease in anti-apoptotic protein BCL2. Unlike its anticancer potential, CsE exhibited clear superior results as an antimicrobial agent with a wider range against six microbial strains, whereas NmE showed a positive antibacterial activity against only two strains.

4N-(2-hydroxy-3-triethyl ammonio-propyl-) fatty-1, 2, 4 triazole-3-thione (12AB) and 2,4N-(bis-2-hydroxy-3-triethyl ammonio-propyl-) fatty-1, 2, 4 triazole-3-thione (12ABB) were synthesized, characterized and tested as surfactant corrosion inhibitors for Mo in 0.01 M HCl solution using galvanostatic, potentiodynamic and potentiostatic polarization techniques. Concentrations of the inhibitors were ranged from 1x10 −6 to 1 (wt. %). The obtained results using galvanostatic polarization on bare metal showed that thickness of adsorbed layer decreased with increasing concentration of 12AB while adverse trend was observed with 12ABB. On the other hand the anodic oxide film formed at 100mAcm-2 up to 0.268V (SCE) was susceptible to a dissolution process with the presence of two corrosion rates for each concentration of the two additives. Potentiodynamic polarization illustrated that increase of additive concentration lowered corrosion current densities affecting anodic reaction more than cathodic one. The protection efficiency increased with increasing inhibitor concentration. The low values of IE. % indicated the presence of electrostatic attraction between inhibiting molecules and the electrically charged surface of metal. Adsorption followed the kinetic thermodynamic model, Langmuir and Flory-Huggins adsorption isotherms. 12ABB showed better inhibiting action than that of 12AB due to the presence of two side chains in its structure. Potentiostatic polarizations indicated that when the concentration of the additives 12AB and 12ABB exceeded a critical value, ≥0.1Wt.%, no inhibition effect.

Tantalum metal was found to serve as an excellent indicator for potentiometric precipitation titrations. The experimental results were discussed in terms of the potential arrests and potential shifts upon addition of the titrant.The obtained results for 0.05M halogen solutions revealed that when tantalum electrode is coupled with SCE or Pt electrodes, sharp potential jumps and distinct end points were obtained in the titration of Cl ֿ, Br ֿ and I ֿ solutions against 0.057M AgNO 3 solution in both forward and backward titration techniques. On the other hand, Ta/Ag systems in forward titrations of Br ֿ and Cl ֿ solutions behave similarly. While in backward titration, the end point is determined by presence of a sharp potential peak in the positive direction. In I ֿ solutions, Ta/Ag system illustrates a sharp potential peak in both forward and backward titration curves. Results for 0.1M halogen solutions revealed that the equivalence volumes in forward titrations for Br ֿ and I ֿ solutions in the four systems are very near to the calculated ones. Concerning Cl ֿ solutions, the volume magnitudes corresponding to the potential jumps are so far from calculated values in all systems used. For I ֿ solution, in backward titration, the order of increasing potential jumps of tantalum systems was as follows: Ta/ Pt < Ta/ Ag < Ta/SCE system. The shape of the titration curves depends upon the kind of halogen and its concentration as well as on the type of system used and type of titration when the experiment is carried out.

The behavior of two steel alloys in phosphoric acid solutions alone and with addition of organic and inorganic compounds was studied using open circuit potential and potentiodynamic polarization techniques. Open circuit potential measurements of the two stainless steel electrodes in different concentrations of H 3 PO 4 showed that the rates of film thickening of the two electrodes are independent of the solution concentration. Potentiodynamic polarizations illustrate that, upon increasing Na 3 PO 4 concentration in 0.5M H 3 PO 4 the pH of the solutions changed in the range from 1.7 to 10.7 and the corrosion rate decreases. Electrode type (II) has inhibition efficiency more than electrode type (I). AT compound (3 amino 1, 2, 4-triazole) has proven to be efficient inhibitor for pitting corrosion of stainless steel in phosphoric acid solutions. The inhibition efficiency was increased by increasing the inhibitor concentration. The inhibitive property may be argued to the formation of a compact FeAT complex film on the electrode surface.

The corrosion behavior of two stainless steel electrodes with different chemical compositions in different salt solutions of Cl¯ ions (NaCl, FeCl3 and HgCl2) was studied. The corrosion behavior in 3.5% NaCl with and without different concentrations of two different triazole derivatives, 3-amino-1, 2, 4 triazole (AT) and 4-amino-5-mercapto-1, 2, 4 triazole (AMT) and Na2S2O3 (50 to 200ppm.) was studied. Open circuit potential measurements, potentiodynamic cyclic anodic polarization (PCAP) and surface morphology techniques were used in this study. Obtained results showed that NaCl is more aggressive comparing with FeCl3 and HgCl2. As the concentration of sodium chloride increased, the (PCAP) curves indicated the presence of pitting or crevice corrosion breakdown potential which sustained the increase of anodic current density. The plots of pitting potential (Epit.), or protection potential (Ep) versus log [Cl¯] at 25 o C, for the two stainless steel electrodes were linearly decreased with the increase of the logarithm of chloride concentration. Also the increase of scan rate increases the localized pitting corrosion. The additions of sodium thiosulphate to 3.5% NaCl enhance pitting corrosion as compared with that found in pure sodium chloride solution. On the contrary, increasing concentration of (AT) and (AMT) in NaCl solution was found to greatly enhance IE%. The adsorptive behavior of the investigated inhibitors on the steel surface followed Langmiur-type isotherm. These results indicate the suitability of the use of the investigated inhibitors. Electrode type (I) has a greater tendency for pitting than electrode type (II) due to the percentage of nickel in electrode type (I) is half that of electrode type (II).